Hello everyone!Did someone knows how many maximum of bgp peers on MX240?We had RE-S-1800x4 with 32G DRAM and JunOS 16.2R2.8
Basically, without that command, you will have a hardware limitation in case that there are tons of routed been received by these devices. The RE you have as 64-bit supports up to RIB 12,000,000 and FIB 5,000,000. We need to keep in mind that those values were taken from dedicated LABs and this varies from the real scenarios where different features are implemented at the same time.The document below will help us to see the interpretation of the knob in question “prefix-limit maximum” and I will quote and commend from the document itself.
DescriptionLimit the number of prefixes received on a BGP peer session and a rate-limit logging when injected prefixes exceed a set limit.We can explicily configure the maximum of prefixes installed from the peer
maximum number—When you set the maximum number of prefixes, a message with peer address, address family and instance name is logged when that number is exceeded.This will add a notification under the log messages
teardown <percentage>—If you include the teardown statement, the session is torn down when the maximum number of prefixes is exceeded. If you specify a percentage, messages are logged when the number of prefixes exceeds that percentage.This is a percentage of prefixes that will be installed while raising a flag in the log messages, this is mostly like a notification.
After the session is torn down, it is reestablished in a short time unless you include the idle-timeout statement.This will be explicit amount of time that will be used as a reference to keep the session down before coming up again. This is in minutes in a range of 1 - 2400
If you specify forever, the session is reestablished only after you issue a clear bgp neighborcommand.Idle-timeout has the option and this option means that the session will be keep down untill the user interfeers.
set routing-instances iad2-fe protocols bgp group LEVEL3_V4 family inet any prefix-limit maximum 1000000set routing-instances iad2-fe protocols bgp group LEVEL3_V6 family inet6 any prefix-limit maximum 1000000
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As checked, we don’t have any Doc for this.Actually, we cannot give a exact number of BGP peers supported for MX240.First of all, all BGP peers are maintained by RE.So the numbers of BGP peers are different when we are using different REs.Second, different JUNOS has different memory limitation for related processes (like rpd, etc).So the numbers of BGP peers are different when we are running different JUNOS.And last, different route numbers, route sizes, policy numbers will consume different memory.And all the factors are dynamic, so it’s hard to give a static number of BGP peers when the routers are in different positions.
Thx for your reply SurajBut how can I know when my limits are coming to an end?In the past, we had a RES-1800 x 4 with 16G RAM and an x86 system. And at some point, we ran into the number bgp sessions ( random ibgp peers starts flapping... ) Now we have ~40 active peers and all the same as we had old processor... And did not establish the source of the problem....
I have that same RE on an mx480 with over 350 peers including three full table and two with 350k and two with 60k, the remainder are maxing at only a couple hundred prefixes received.
I was informed by my SE that we can have 20million active routes from all Virtual routers before seeing BGP routing limitations.